Hironori Yoshimura

Characteristics of thin film growth in the synthesis of diamond by chemical vapour deposition and application of the thin film synthesis technology for tools

Abstract Diamond films were synthesized under various reaction conditions by hot-filament thermal chemical vapour deposition (CVD). Under reaction conditions of a low total pressure, or a high CH 4 concentration, or a long distance between the filament and the substrate, the surface morphologies of diamond films are of a very-fine-grained coagulated spherical structure. In these cases, strong peaks of amorphous carbon phases in laser Raman spectra were detected. From reflection high energy electron diffraction results and X-ray diffraction analysis, it was concluded that an amorphous carbon phase exists on the surfaces and also between the grain boundaries of diamond polycrystals. Cutting performance tests were carried out to investigate the possibility of utilizing CVD diamond films as a wear-resistant coating for cutting tools. It was also concluded that the CVD diamond coating on cemented-carbide inserts is an effective means of prolonging the life of the insert for turning non-ferrous metals, and, in particular, aluminium alloys and semisintered ceramics.